Flexible cord



W. L. RUNZE..

FLEXIBLE CORD. I APPLICATION msn 51H19, 1911. 1,340,839, Patented May 18,1920.

UurrED Asfiga-rms PATENT orrrca WILLIAM L. RUNZEL, OF CHICAGO, ILLINOIS, ASSIG-NOR TO RUNZEL-LENZ ELECTRIC MFG". CO., OF CHICAGO, ILLINOIS.

FLEXIBLE CORD.

- Application med May 1'9,

To all 'whom t may concern Be it known that I, WILLIAM L. RUNZEL, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Flexible Cords, of

y which the following is a full, clear, concise,

and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to Hexible cords and more particularly to that kind of a flexible cord made up of conducting elements for tive purposes as the application of my invention to equivalent uses will be readily apparent.

In the manufacture of switchboard cords, for instance, where these have at least two separate and'distinct conductors itis necessary to provide conducting means which are of course adequate for the purposes in hand. At the same time these flexible cords must be so constructed that they willbe capable of much hard usage. he very nature of` the use of flexible cords makes it imperative that the wearing qualities are of the highest importance. 'The problem presented by this state of things includes the proper selection of conducting 4elements flexible in their nature so vthat repeated bending will not destroy their continuity. p

There has been developed in answer to this demand a connecting cord in which at least one of these conductors is helically wound and some in which both conductors are helically wound. These conductors are made of steel or similar material, not because steel is the best conductor, but primarily on account of its ability to remain unbroken through a period of long continued use. In order to provide the necessary conductivity tinsel conductors made of copper are frequently added and laid in metallic contact along the helical conductor. My invention concerns itself with the provision of one or more conducting elements for a 'flexible cord, which shall have the requisite conductivity without the necincreasing devices are absent.

Specification of Letters Patent. Patented BIay 18, 1920.

Serial No. 169,616.

essary reinforcement of tinsel or other' auxiliaries, and which shall at the same time be able to maintain its character under the heavy service to which such cords are subjected. In this manner the use of composite conductors or similar expedients is entirely avoided.

I have found that by the use of a helically Wound phosphor bronze conductor I obtain in one element those necessary qualities hereinbefore discussed. The phosphor bronze conductor has the required conductivity and at the same time has the required durability.

My improved cord likewise has a feature very desirable in this connection and that is to so arrange the cord that the conductors thereof each have an equal amount of resistance. It will be readily clear that when two helically wound conductors are used, one wound about the other, that the diameter of the convolutions of the outer vconductor effected in that way. When the cord however, as in this invention, is designed to use merely two helically wound conductors (when applied to a two conductor cord for instance) then these auxiliary conductivity In order to balance a cord of this kind so that the conductivity of both. conductors will be the same, I construct the outer helical ,conductor of a wire of increased gage so that the resistance of this outer conductor, even though the conductor is longer than the inner conductor will be the same or substantially the same as that of the inner conductor.

In the accompanying drawing I illustrate one form in which my invention may be embodied. In this drawing- Figure l is a side view of the cord of my invention as applied to a two conductor cord showing the arrangement of the conductors and the various wrappings, and

Fig. 2 is a sectional view on line af-a of Fig. 1. l

By referring to the .drawing I show a central core l which is preferably of jute rope about which is helically wound the conductor 2 made of phosphor bronze. This phosphor bronze conductor is of course very flexible, but'very tough and has great durability under Athe service required of it. About this conductor 2 there is bound a suitable layer of insulating material such as silk, cotton or wool, whicl again is surrounded by a' braid 4 of somewhat similar material. About this is helically wound the conductor 5 likewise `of phosphor bronze.l

This outer conductor, as will 'be apparent has a larger diameter than the inner conductor 2. Thus by increasing thediameter of the outer conductor the resistance of the two conductors of the cord can be made the-` same even though the outer conductor has convolutions of larger diameter than ,that of the inner conductor. About thelconductor4 5 there is then a suitable insulating wrapping G, which may be moisture proof if desired, about which is plaeed the ordinary covering 7 of insulation customary in cords` of this nature. a

, It will thus be seen that the entire conducting portions of this cord are the con ductors 2 and 5, these being helically wound and formed of phosphor bronze wire. The two qualities of durability and conductivity are thus combined in each of these elements 2 and 5 so that no other provision need be made in the cord for conducting purposes but merely for insulating purposes.

From what has been thus described the nature of my invention will be readily clear to those skilled in the art.

Having however thus described one form whichrny invention may take, what I 'claim as new' and desire to secure by Letters Patent is: f

1. A flexible conducting cord of the character described lcomprising two concentric helicall Awound conductors, the outer conductor being larger in cross section than the inner conductor to equalize the resistance of the two conductors'.

25 A flexible conducting cord of the charlacter described comprising two concentric helically Wound conductors made of phos! phor bronze, theouter conductor beingA larger in cross section than the inner con'- ductor to equalize the resistance of the two conductors.

`In witness whereof, I hereunto subscribe rny name this 13th day of April, A. D.1 9l7.

Wim-1MM L. RUNZEL.. j

4Witnesses 1 Y HAzEL A. JONES,

MAX W. ZAB'EL. 

